P1297: CLINICAL PROGNOSTIC MODEL OF OSTEONECROSIS OF THE FEMORAL HEAD AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION
Authors: Bo Yang, Xiao-Lu Zhu, Hai-Xia Fu, Chen-Hua Yan, Yuan Kong, Yun He, Feng-Rong Wang, Yuan-Yuan Zhang, Xiao-Dong Mo, Wei Han, Jing-Zhi Wang, Yu Wang, Huan Chen, Yu-Hong Chen, Xiang-Yu Zhao, Ying-Jun Chang, Lan-Ping Xu, Kai-Yan Liu, Xiao-Jun Huang, Xiao-Hui Zhang
Journal: HemaSphere (2023)

Topic: 22. Stem cell transplantation - Clinical Background: Osteonecrosis of the femoral head (ONFH) is a common complication after allogeneic haematopoietic stem cell transplantation (allo-HSCT) in the orthopaedics field. Severe ONFH patients are usually treated with total hip arthroplasty (THA), which imposes substantial disability and interferes with activities of daily living. However, there is no information available on the prognostic factors of ONFH after allo-HSCT, and there is also no prognostic model for ONFH after allo-HSCT. Here, a prognostic model that combined clinical and imaging risk factors to predict the risk for THA in ONFH patients precisely after allo-HSCT was developed and validated. Aims: The aim of this study was to develop a prognostic model for identifying posttransplant ONFH patients who are at a higher risk of THA. Methods: We retrospectively analysed 164 ONFH patients after allo-HSCT to develop and validate the prognostic model. The derivation cohort consisted of 102 patients, and the validation cohort consisted of 62 patients. We used a logistic regression model to perform univariate and multivariate analyses to determine the prognostic factors for ONFH after allo-HSCT. Variables with p < 0.1 in univariate analysis were further included in the multivariate analysis according to the outcomes of the multivariate analysis in the derivation cohort. We performed an internal verification process with 1000 bootstrap resamples. Furthermore, we used an independent cohort for external validation. The discrimination ability of the prognostic model was computed using the area under the receiver operating characteristic curve (AUC), while the calibration power was analysed with a calibration plot. A decision curve analysis (DCA) was used to calculate the net benefit. Results: Post-transplant ONFH occurred in 164 of 7,707 allo-HSCT patients. ONFH was diagnosed at a median of 674 days after allo-HSCT (ranging from 0 to 3652 days). A total of 130 patients presented bilateral involvement of the femoral head, and 34 had unilateral involvement. The median follow-up period for each case was 926 days (range 0 to 4033 days). Thirty-five patients required THA. Univariate analysis showed that age, alcohol consumption, smoking, donor type, time from HSCT to ONFH, aGVHD, claudication, limited hip movement and ARCO score were significantly related to the prognosis of post-transplant ONFH (p<0.05). In the following multivariable analysis, the results showed that smoking, donor type, claudication and ARCO score were independent prognostic factors for ONFH following HSCT (p<0.05). Therefore, a prognostic model was then developed, which was named ASDC (ARCO score>2, smoking, donor type and claudication). The ASDC prognostic model showed significant discriminatory capacity. The c-statistic was 0.897 (95% CI, 0.784-1.011) in the internal validation using the bootstrap method and 0.785 (95% CI, 0.662-0.909) in the external temporal validation. The calibration plots also indicated optimal consistency between the model-predicted and actual observed probabilities. A decision curve analysis (DCA) also showed a positive net benefit for a wide range of probability thresholds in both internal and external validations. Summary/Conclusion We developed a prognostic model that combined clinical and imaging risk factors to identify the risk for THA in ONFH patients precisely following allo-HSCT. This model can be effectively used to help improve the prognosis of ONFH patients by accelerating the early identification of patients at high risk of THA. Keywords: Allogeneic hematopoietic stem cell transplant, Prognostic factor, Osteonecrosis